Flexible shafts comprise basic elements of power transmission and are designed to transmit power or control from a driving element to an element to be driven. Transmission may be over, under, or around obstacles or objects where transmission by solid shafts would be impractical or impossible.
In a typical rotatable flexible shaft, a wire mandrel has a plurality of layers of closely coiled wire wound thereover, each of the layers being successively wound over another in alternately opposing directions, i.e., right or left-hand lay. This shaft is usually covered by a flexible casing, metallic or covered, and a clearance between the shaft and casing is provided in order that the shaft may rotate freely within the casing.
Rotatable flexible shafts are of two basic types--power driven and remotely controlled. Power driven flexible shafts are designed primarily for motor-driven or high speed operation in one direction. Remote control flexible shafts, on the other hand, are designed primarily for hand-operated control in either direction.
Power driven flexible shafts have two general classes of application--those in which there is relative movement between the driving and driven elements, and the curvature and twisting of the shaft is continually changing, as when, for example, a driven element such as a portable grinding tool is continuously moved about the workpiece by an operator and those in which the shaft operates in a given position and the curve, or curves, of the shaft remain substantially fixed, as in the coupling arrangement of the present invention wherein a shaft is used to transmit torque from a motor to a pump, or motor to a blower, for example. In a typical arrangement of this type, a fitting is permanently affixed to each end of the flexible shaft and the fitting suitably respectively connected to the output shaft of the motor and input shaft of the driven member.
Such practice necessitates an inventory of a rather large number of flexible shafts in order that (a) coupling torque requirements between the driving and driven members may be readily satisfied, and (b) the permanent fittings at the flexible shaft ends will, in all likelihood be compatible with the various sizes of shafts of the driving and driven members.
The present invention permits a much smaller inventory of flexible shafts to be stocked and yet each of the inventoried shafts may be used to couple any one of several driving members to any one of several driven members.
Briefly, a flexible shaft is provided with integrally-formed, polygonally-shaped ends, preferably square, which are slidingly, free-floatingly received by adapters having bores at their other ends of different sizes. Thus, a torque conveying coupling system is described herein wherein the same flexible shaft may be used between one of a plurality of driving members and one of a plurality of driven members, each of the members having identical or different size shafts by merely, if necessary, selecting adapters with proper bore sizes.